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Re: ?Secondary coil questions?
Original poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx>
Hi Jay,
The resonant frequency calculation for the secondary coil is 1 / (2 x
PI x SQRT(L x C)). The secondary's winding has an inductance (L) and
a capacitance (C). The inductance is based on wire size, geometry,
and current distribution. The capacitance is due to the capacitance
between each turn. Those are the "basics". However, not all is
included in this simple equation. Tesla Coils are air core
transformers. The secondary is easily influenced by external
capacitances and by the distribution of currents along the coils
length which becomes less uniform at high frequency and in the
presence of external capacitances. The main external influences are
ground, objects near the coil, the primary, toploads, and the
surroundings where the coil is measured or run. Their size and shape
affect the self resonant frequency of the coil because both L and C
will vary with their influence.
So, we use programs (as Terry explained) to figure out as many
"influences" into the calculations as is humanly possible. The
programs include many years of work, but that is usually not
realized. It helps to understand just what the programs are doing and
often it's good to measure and test measurements against program
predictions. Terry, Carlos, Paul, and my own Javatc programs are very
good at figuring out the L's and C's. There are some slight
differences in our methods, but our results are extremely close.
Only a few years ago, the toploads influence was completely empirical
and calculations simply used a percentage of influence to predict
frequencies. Nowadays, we are actually computing the size, shape, and
positional influence on the coil. This also includes the primary's
external capacitance on the secondary. These are things best left to
programs. Measuring is always an excellent cross check and I
recommend that everyone measure as much as possible. Just keep in
mind that when C and L is measured, such as a simple LCR meter, the
measurements are for L's and C's where currents are uniform along the
coil. It can be difficult to measure these things at resonant
frequencies when the currents are not uniform. Thus, it takes
specific equipment and methods, so good programs written specifically
for Tesla resonators are very helpful.
All these programs are a direct result of Chip's TCML over these many years.
There is a document that Terry wrote which is very helpful for
coilers regarding calculations. It's at his site and also at my own.
<http://www.classictesla.com/FormulasForTeslaCoils.pdf>http://www.classictesla.com/FormulasForTeslaCoils.pdf
Some of the programs at my site are:
<http://www.classictesla.com/java/javatc.html>http://www.classictesla.com/java/javatc.html
(JAVATC - A Tesla Coil Design program)
<http://www.classictesla.com/fantc/fantc.html>http://www.classictesla.com/fantc/fantc.html
(FANTC - A program to solve C's and L's).
<http://www.classictesla.com/java/javammc/javammc.html>http://www.classictesla.com/java/javammc/javammc.html
(JAVAMMC - MMC Design Program)
<http://www.classictesla.com/java/2layer/duallayer.html>http://www.classictesla.com/java/2layer/duallayer.html
(Dual-Layer Primary Inductance program)
<http://www.classictesla.com/java/platecap/platecap.html>http://www.classictesla.com/java/platecap/platecap.html
(Plate Capacitor Design program)
<http://www.classictesla.com/java/rollcap/rollcap.html>http://www.classictesla.com/java/rollcap/rollcap.html
(Rolled Capacitor Design program)
<http://www.classictesla.com/java/bottlecap/bottlecap.html>http://www.classictesla.com/java/bottlecap/bottlecap.html
(Jar or Bottle Capacitor Design program)
Antonio Carlos M. de Queiroz has a bunch of excellent programs at:
<http://www.coe.ufrj.br/%7Eacmq/programs/>http://www.coe.ufrj.br/~acmq/programs/
Terry Fritz also has programs at:
<http://hot-streamer.com/TeslaCoils/Programs/Programs.htm>http://hot-streamer.com/TeslaCoils/Programs/Programs.htm
Paul Nichoson's TSSP site is filled with a great deal of up to date
theory and TSSP software:
<http://www.abelian.demon.co.uk/tssp/>http://www.abelian.demon.co.uk/tssp/
Mark Rzeszotarski has an excellent Matual Inductance and Coupling
program (MandK):
<http://hot-streamer.com/TeslaCoils/Programs/MANDKV31.ZIP>http://hot-streamer.com/TeslaCoils/Programs/MANDKV31.ZIP
http://hot-streamer.com/TeslaCoils/Programs/MANDKV31.PDF
More than you probably wanted with a simple question, but now and
then it's good to point out some of these programs for the entire
list. Many new coilers may not be aware of all the programs available.
Take care,
Bart
Tesla list wrote:
Original poster: <mailto:jhowson4@xxxxxxxxxxx>jhowson4@xxxxxxxxxxx
Question
How do you calculate the resonance frequency of the secondary coil
with or with out a top load?
Jay Howson
<mailto:jhowson4@xxxxxxxxxxx>jhowson4@xxxxxxxxxxx